function s1_generate_a_series_of_files(){
for i in {1..100};do 
echo $i>/tmp/new_file$i;done
}

function s2_lise_4_files_in_long_format_about_account_and_group(){
ls -l /etc/{passwd,shadow,group,gshadow} | sort -d
}

function s3_find_items_related_to_given_group_name(){
 grep -h $1 /etc/{passwd,shadow} | sort -d
}

function s4_find_items_related_to_given_group_names(){
 grep -h $1 /etc/{group,gshadow} | sort -d
}

function s5_create_groups_for_given_group_names(){
 groupadd rnd && groupadd itoperation
}

function s6_create_users_and_set_their_group_as_required(){
 useradd -G rnd adam && useradd -G rnd bob && useradd -G itoperation calvin && useradd -G itoperation david && useradd -G rnd edward
}

function s7_change_users_shell(){
 usermod -s /usr/bin/sh adam && usermod -s /usr/bin/sh edward
}

function s8_set_password_change_poliy(){
passwd -n 10 -x 60 -w 10 adam
passwd -n 10 -x 60 -w 10 bob
passwd -n 10 -x 60 -w 10 calvin
passwd -n 10 -x 60 -w 10 david
passwd -n 10 -x 60 -w 10 edward
}

function s9_set_password_for_five_users(){
   username=(adam bob calvin david edward)
  for i in $(seq 1 5); do
echo ${!i};
echo $(($i-1));done
echo "${username[0]}:$1" | chpasswd
echo "${username[1]}:$2" | chpasswd
echo "${username[2]}:$3" | chpasswd
echo "${username[3]}:$4" | chpasswd
echo "${username[(($i-1))]}:$5" |chpasswd
}

function s10_lock_bobs_password(){
usermod -L bob
}

function s11_include_adam_into_wheel_group(){
user -a -G wheel adam 
}

function s12_change_files_permission(){
for i in {i..33}; do
chmod -R 640 /tmp/new_file$[3*i];done
}
